<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <script>
  // let arr=new Array(1,2,3)
  // console.log(arr)
  let person={
    4:'yay',
    name:'zhangsan',
    age:18,
    sing:function(){
      console.log('唱歌')
    }

  }
//   let name='4'
//  console.log(person[name])
person.age1=20
delete person.age
console.log(person)
//  console.log(person.name)
//  console.log(person['name'])
  // console.log(person.name)
  // person.sing()
  </script>
  
</body>
</html>